Chevrolet Repair: transmission wont go into park, linkage, blazer

Question
all of a sudden my 99 blazer will not go into park. if i crawl under the truck and push the linkage it will go into park but not by using the gear selector, it will only go into reverse

Answer
HI TOM,THE FACT THAT YOU CAN MANUALLY PUT THIS IN PARK, WE KNOW THIS IS EITHER A LINKAGE ADJUSTMENT PROBLEM OR THE LINKAGE DOWN BY THE TRANSMISSION IS BENT CAUSING THIS PROBLEM. DID YOU DO ANY OFF ROADING ??? IF NOT, THEN WE WILL RULE THE BENT LINKAGE OUT OF THE PICTURE. CK DOWN BY THE TRANS AND CK THE CABLE HOOK UP.THERE SHOULD BE A NUT THAT HOLDS THE CABLE TO THE LINKAGE, LOOSEN THE NUT AND MOVE THE CABLE SO IT PUSHES THE LINKAGE TO MOVE FURTHER IN THE DIRECTION THAT YOU NEED IT TO GO AND THEN TIGHTEN IT UP THERE IN PLACE..IF THIS CORRECTS THE PROBLEM IT MAY ONLY BE TEMPORARLY,THE CABLE MAYBE GETTING READY TO BREAK. SO, IT STRETCHED,, ONLY TIME WILL TELL. IF THIS DOES NOT CO0RRECT IT,,, IT IS POSSIBLE THAT WHERE THE CABLE IS HOOKED TO THE BRACKET IS BECOMING WEAK AND MOVING AROUND CAUSING THIS..HAVE SOMEONE GET IN THE TRUCK AND MOVE THE SHIFTER FROM PARK TO LOW 1 AND YOU GET UNDER THE TRUCK AND WATCH. WATCH IF ALL THE BRACKETS LOOK GOOD AND SECURE. MAKE SURE YOU ARE ON LEVEL GROUND PLEASE !!!! LET ME KNOW ,,TOM...